bob orr was given top secret clearance and has this story. >> reporter: the terrorist screening center is home to the nation's top secret information on suspected terrorists. it's so sensitive, we were asked not to record any of the sounds inside this room. and we agreed to identify only director tim healy, a veteran fbi agent who oversees the terrorist watch list of 520,000 names. >> that could be a facilitator, it could be a bomber, could be a bomb maker, anybody. anybody connected to terrorism. >> reporter: this clearinghouse of terrorist information is used every day by tsa officers, border agents, and state, local, and federal law enforcement. >> if you're speeding, you get pulled over. they'll curry that name, and if they're encountering a known or suspected terrorist, it will pop up and say call the terrorist screening center. >> reporter: how often do these encounters say? >> we're averaging about 55 encounters with known or suspected terrorists every day. >> reporter: in most cases, the encounters do not lead to arrest but provide additional intelligence. >> location of where